The present invention relates to a device for actuating a system such as a clutch or a gearbox associated with an engine, particularly a motor vehicle engine, and of the type comprising control means and an actuation member.
There currently exist various types of mechanical gearbox with or without automatic clutch, and automatic gearboxes.
Mechanical gearboxes are also known in which both the gear change and the clutch are automatically controlled. Such automatic control involves complex and thus costly hydraulic or electrical systems which are difficult to maintain and consequently reserved in practice, until now, for competition vehicles.
The present invention aims particularly to provide a device making it possible to offer assistance to driving a motor vehicle which is simple and relatively inexpensive, and more particularly making it possible to assist the gear-change and clutch-engagement maneuvers.
Document FR-A-877,118 discloses a device for actuating a system such as a clutch or a gearbox associated with an engine, particularly a motor vehicle engine, and comprising control means and an actuation member, and furthermore including:
a first shaft rotationally driven by the engine, PA1 a second shaft integral with the actuation member, PA1 coupling means for coupling the second shaft to the first shaft under the action of the control means, PA1 means for uncoupling the second shaft from the first shaft after the second shaft has rotated through a predetermined angle, and PA1 return means for returning the second shaft to its initial position after it has been uncoupled from the first shaft.
More particularly, the coupling means are made up of a friction clutch including friction members, some of which are designed to be driven by the first shaft, and others of which are capable of driving the second shaft.
The friction members are coaxial with the first shaft, the first friction members being rotationally integral with the first shaft and the second friction members being rotationally integral with a support member itself rotationally integral with a gear wheel meshing with a toothed sector rotationally integral with the second shaft.
This is therefore a mechanical device whose energy source consists of the engine itself. The power takeoff may, of course, be located in the region of the output shaft of the engine or further downstream, for example on the output shaft of the gearbox. The control member in this case is produced in the form of a pedal.
This device consequently operates like a mechanical amplifier of the force exerted by the user.
It, however, exhibits the drawback that the user must make his action last until the end of the operating cycle. If the user fails to keep a continued force on the pedal to the end of the operating cycle, this cycle is interrupted and the operation of the device and of the members which it controls is disturbed.